Cephissus , Kifissós) or Cephisus Kifisos), a river flowing through the Athenian plain.

In his summary of Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

 Apollodorus

Apollodorus

Apollodorus of Athens son of Asclepiades, was a Greek scholar and grammarian. He was a pupil of Diogenes of Babylon, Panaetius the Stoic, and the grammarian Aristarchus of Samothrace...

 (3.15.1) declares that Erechtheus

Erechtheus

Erechtheus in Greek mythology was the name of an archaic king of Athens, the re-founder of the polis and a double at Athens for Poseidon, as "Poseidon Erechtheus"...

' wife Praxithea was daughter of Phrasimus (otherwise unknown to us) by Diogenia (otherwise unknown to us) daughter of Cephissus.

This river is found in the western part of the valley. Today much of the river flows adjacent to the freeway

Greek National Road 1

The Greek Motorway 1 is a motorway, partly under construction, and the 2nd longest in Greece. It is the principal north-south road connection in Greece, connecting the country's capital Athens with the regions of Thessaly and Macedonia, as well as the country's second largest city,...

 linking Athens and Thessaloniki, and east of mountains of Parnitha

Parnitha

Mount Parnitha is a densely forested mountain range north of Athens, the highest on the peninsula of Attica, with an elevation of 1,413 m and a summit known as Karavola...

 and Aegaleo.

• Length: ?km/?mi
• Empties into: Saronic Gulf
  Saronic Gulf
  The Saronic Gulf or Gulf of Aegina in Greece forms part of the Aegean Sea and defines the eastern side of the isthmus of Corinth. It is the eastern terminus of the Corinth Canal, which cuts across the isthmus.-Geography:The gulf includes the islands of; Aegina, Salamis, and Poros along with...
  
  

In the southern part, the river flows for 15 km under (but originally in the middle of) the highway named Kifissou Avenue.

Kifissou Avenue Freeway

After the Olympics of 2004

2004 Summer Olympics

The 2004 Summer Olympic Games, officially known as the Games of the XXVIII Olympiad, was a premier international multi-sport event held in Athens, Greece from August 13 to August 29, 2004 with the motto Welcome Home. 10,625 athletes competed, some 600 more than expected, accompanied by 5,501 team...

, the Kifissou Avenue freeway, now with three to four lanes, runs for 15 km over the river because of lack of space of housing in the Athens area. It will also connect Piraeus

Piraeus

Piraeus is a city in the region of Attica, Greece. Piraeus is located within the Athens Urban Area, 12 km southwest from its city center , and lies along the east coast of the Saronic Gulf....

, from the northern suburbs and the communities of south suburban Athens

Athens

Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

 from Varkiza

Varkiza

Varkiza , also Alianthos is a partly urbanised area forming part of the municipality of Vari-Voula-Vouliagmeni in southern Attica, located east of the Megalo Daktylo...

 to Phaliron. This will decongest Athens' downtown streets.

History

Construction began in 1995 and with four bridges being torn down for widening. Work has continued for nearly eight years. However, heavy rains and flooding delayed work over the river (first week of August 1997) causing a cement truck to wash away. In 1999, the reconstruction of Treis Gephyres, (the Three Bridges) was being repaired for widening.

In the later phases of construction, the new freeway extended to near Peiraiôs Avenue when heavy rains delayed the construction in mid and late 2002, one in mid-July

July 2002

July 2002: January – February – March – April – May – June – July – August – September – October – November – December-July 1, 2002:* A Russian Tupolev Tu-154 airliner and a Boeing 757 operated by DHL collide at 35,000 ft over Uberlingen, due to failure of correct communication from...

, and about three in September

September 2002

September 2002: January – February – March – April – May – June – July – August – September – October – November – December- September 1, 2002 :...

. Flooding has also occurred. Gates were being put to prevent flooding. This was the year of heavy rains. The freeway over the Kifissos or the Cephissus made it down to the freeway (not far where the river ends) linking the southern suburbs and Athens from Piraeus which is also Poseidonos Avenue for its final phases owidening GR-1. This will end with opening a southern junction near the new Olympic facility. It will open around mid-2004.